MacOS – Mounting a disk as though it were an external disk

macosmounttime-machinetruecrypt

Here's the setup:
We have a corporate Time Capsule (or series of them, rather) with encrypted backups in the server closet. My Mac currently backs up to that.
I've just completed encrypting an internal disk using TrueCrypt, and set it up using a .sh executable that launches at login. For the curious, it reads:
/Applications/TrueCrypt.app/Contents/MacOS/TrueCrypt --mount -v /dev/rdisk1s2 and rdisk1s2 is an internal disk on my mac, so as long as the password is correctly supplied, it should be available at all times. So far so good. When it mounts, it appears to the OS as though it were a .dmg.

And that's where things get hairy: I'd like to make sure my encrypted volume gets backed up to the Time Capsule. However, because Time Machine doesn't 'like' mounted disk images (apparently because it wants to preserve some vital assumptions regarding the availability of this disk…) it doesn't recognize the disk to back up.

So the question at this point is: How does one go about 'tricking' Time Machine into thinking the disk is back-up-able?

Thus the title: How does one go about referencing a mounted disk to make it appear to the OS as though it was internal?

Best Answer

It looks like you're not the only person with this question. As a workaround, could you use FileVault 2 for full-disk encryption instead? That does play well with Time Machine.

More information about why this doesn't work at Backup mounted drive of an image in Time Machine.